<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
		<style type="text/css">
			#box{
				border: 1px solid #000;
			}
		</style>
	</head>
	<body>
		<div id="box"></div>
		<table>
			<tr>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
			</tr>
			<tr>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
			</tr>
			<tr>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
			</tr>
			<tr>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
				<td>Header</td>
			</tr>
		</table>
		<script src="js/jquery-3.4.1.js" type="text/javascript" charset="utf-8"></script>
		<script type="text/javascript">
			
			$(function(){
				// $("#box").Width("100px");
				$("#box").css(
					{"width":"200px","height":"200px"}
				);
				$("#box").hide();//隐藏
				$("#box").show();//显示
				$("tr").eq(2).css("background-color","red");
			});
			
		</script>
	</body>
</html>
